Fans



Oct- 23, 1962 R. A. BENolT 3,059,833

FANs

Filed oct. 1m 1958 z shees-sneet 1 16' FIM;

I N VEN TOR. few; a' A. 3800z R. A. BENOIT Oct. 23, 1962 FANS 2Sheets-Sheet 2 Filed Oct. l'7 1956 IN V EN TOR. I wf A 36/701;

United States Patent O Filed Oct. 17, 1956, Ser. No. 616,458 6 Claims.(Cl. 230-119) The present invention relates to rotary fans, and hasspecial reference to multi-blade fans or blowers.

Both centrifugal fans and axial fans, at present in general commercialuse, have certain disadvantages.

Centrifugal fans take up considerable floor space and, consequently,their use is restricted. Also, in the case of centrifugal fans having aspiral housing, in order to make the assembly compact as well as toreduce costs, the housing must be made much wider than the wheel. Insome instances, inasmuch as the air must distribute itself laterally asit enters the housing, the mechanical efliciency thereof issubstantially reduced. Also, centrfugal fans cannot be used whenstraight line flow is desired.

Axial fans are designed for straight line flow but, when employed wheresubstantial resistance is encountered, are very noisy and, hence, theiruse is restricted chiefly to industrial purposes, they being unsuitablefor air-conditioning and general ventilating purposes where quietness isessential. Also, such fans are not usable over their entire pressurerange, from wide open volume to no delivery. In some instances, volumeselections can only be made over substantially one-third of the pressurerange if stable operation is desired.

One of the objects of the present invention is to provide a fan orblower which overcomes the disadvantages above described of bothcentrifugal fans and axial fans, while retaining the advantages thereof.

Another of the objects of the invention is to provide a fan or blower ofthe Character indcated which is simple in construction and highlyefficient in operation.

The several features of the invention, |whereby these and other objects'may be attained, will be readily understood from the followingdescription and accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view, partly in elevation, of a fanembodying features of my invention in their preferred form, the sectionbeing taken on line 1-1 of FIG. 2, and the driving means of the fanimpeller being omitted;

HG. 2 is a transverse sectional view, taken on the line 2-2 of FIG. 1;

FIG. 3 is a schematic view of one of the vanes in the cylindricalhousing of the fan, illustrating the preferred curvature of the vanewith relation to the impeller;

FIGS. 4, 5, 6, 7, 8 and 9 respectively show quarter views of the frontsides of impellers having their blades of different forms;

PIG. 10 is a view corresponding to FIG. 1 of a modified form, the fanbeing shown as belt driven;

TG. ll is a rear elevation of the same;

PIG. 12 is a view corresponding to FIGS. 1 and 10 of another modifiedform, the impeller being shown directly connected to the shaft of anelectric motor;

FIG. 13 is a rear view of the same; and

FIG. 14 is a schematic view illustrating that the curvature of the vanesat their intersection with the surface of the fan housing, whenprojected by revolutions to a plane, is substantially the involute of acircle.

The fan illust-rated in FIGS. 1 and 2 of the drawings is provided with acentrifugal impeller 2 having a hub 4 which is adapted to be secured onthe shaft of an electric motor or connected with other driving means(not shown).

The impeller has a backplate 6 secured on the rear ICC end of the hub 4,blades 8 which project radially from the hub, and a shroud 10. An inletcone 12 forms a continuation of the shroud 10. The fan is furtherprovided with a stationary dscharge thimble 14 which has its front edgearranged closely adjacent the rear edge of the backplate 6. The shroud10 is preferably secured to the blades so as to be carried thereby.However, the shroud may be stationary, in which case it may be madeintegral with the inlet cone.

The fan is provided with a cylindrical housing 16 'which has annularangle irons 18 secured on the outer side of its front and rear ends, towhich supporting means for the fan may be secured. The front end of thehousing 16 has the front end of the inlet cone 12 secured thereto.

The cylindrical housing 16 has volute-shaped vanes 24 secured to theinner cylindrical surface thereof. These vanes 24 extend generallylongitudinally of the inner surface of the housing, and the innercorners of their leading ends make contact with the outer surface of thedscharge thimble 14, said corners being in proxirnity to the front edgeof the thimble and, consequently, close to the inner corners of thetrailing edges of the impeller blades. The thimble may be secured to theends of the vanes so as to be supported thereby in fixed position.

The air enters the fan through the inlet cone 12 which directs the airto the intake of the impeller 2 along its blade-leading edges 26.Centrifugal force is imparted to the air as it passes between theimpeller blades 8, and the air is discharged from the impeller throughthe area formed by the trailing edges 27 of the blades, the rear edge ofthe shroud 10 and the backplate 6. Thence, the air enters the confinesof the cylindrical housing 16, thimble 14, and the vanes 24. The airpasses from the vane leading edges 28 which are the points of cut-off ofthe air, to their trailing edges 30, the air leaving the fan throughhousing dscharge 32.

The impeller 2, shown in FIG. 1, is of the paddle wheel type with longradial blades 8. The outer ends of the blades are extended outwardly in=more or less of an inverted V-shaped form, the extended ends havingtheir front edges 25 inclined outwardly and rearwardly, and their rearor trailing edges 27 inclined inwardly and rearwardly to the rearannular edge of the backplate 6.

These extensions of the blades 8, together with the shroud, provideeffective means of directing the air in the general direction ofultimate dscharge with minimum turbulence or losses. Also, saidextensions of the blades permit the use of a larger inlet, at the sametime maintaining proper blade depth. Both increased inlet size andgreater peripheral speed of the extended blades add materially to thepressure produced by the impeller.

The thimble 14, as shown in FIG. 1, is positioned with its front edge inrunning clearance with the rear annular edge of the backplate 6. Thebackplate may be extended to form the thimble 14, in which case theextension should have running clearance -with the front ends of thevanes 24. Higher pressures are produced when the eX- treme diameter ofthe backplate 6 exceeds the smallest inner diameter of shroud I10, thisbeing due primarily to the radially diverging path the air is compelledto take when moving rearwardly from the region of the smallest innerdiameter of shroud 10 and around backplate 6.

It is important that the corners of the leading edges 28 of vanes 24 bepositioned within the width of the thimble C14, and preferably in closeproximity to the front annular edge of the thimble. Also, the leadingedges 28 of the vanes should be inclined outwardly and rearwardly asshown with relation to the thimble '14 and the trailin-g edges 27 of theblades. This arrangement eifectively eliminates turbulence and noise atthe point of cut-off of the air stream leaving the inclined trailingedges 27 of the blades.

The vanes 24 should be so positioned in the cylindrical housing 116 thattheir surfaces are substantially orthogonal to the tangent at theirpoint of contact with the inner cylindrical surface of the housing.

I have found that the straight and thin leading edges 28 of the vanes 24at the points of cutoff, were more eicient than blunt edges, thisapparently being due to the sharpness of the cutoif. I have also foundthat for quiet operation the best results are obtained, with the leadingedges 28 cut in a manner as to be disposed diagonally to the trailingedges 27 of the impeller blades. The best performance, so 'far asquietness is concerned, with the impeller shown in PIG. 1, was obtainedwhen a line parallel to the leading edges 28 of the vanes followed adirection toward the impeller inlet, while converging to- Ward theimpeller axis as shown.

Actual tests of my new fan, with the diameter of backplate 6 equal tothat of commercial centrifugal fan impellers in a spiral housing, gavehigher efiiciency for the same Volume and pressure at equivalentrotative speeds.

With my new fan as shown in FIG. 1, a pressure curve was obtained wherethe pressure rises constantly without dips from wide open volume to nodelivery. In other words, stability of volume discharge is obtained overthe entire pressure range.

The total pressure or head produced by a centrifugal impeller may beutilized by converting various portions of kinetic energy into staticpressure. The amount of this conversion depends on the design of themeans employed for effecting it. It is desirable to convert part of theVelocity pressure of the air leaving the blades to static pressure. Thisstatic pressure is usable to overcome restrictions such as duct work, orto overcome the resistance of the system through which the air passes.It is desirable that the conversion of the state of the air beaccomplished with minimum losses. The curvature of the vanes 24 inrelation to impeller and housing is of great importance.

Since the conversion of kinetic energy of air to a required state ofstatic pressure is in effect a conversion of high rvelocity to a lowerVelocity, the differential in the respective Velocity heads is equal tothe static pressure thus obtained. This state of conversion may beaccomplished by gradual increase in area immediately after the airleaves the blades together with means of receiving the air at itsinitial high Velocity. Also, the conversion device should eliminate thespin of the air in the housing. I have found that with my improved fanhaving the vanes 24 curved and arranged as shown, it accomplishes all ofthese functions.

The air leaves the impeller blades in a path indicated by the Vectors inFIG. 3. It will be observed that each baffle vane.s convexed surface orfront side immediately beyond its leading edge 28 diverts the air in itspath of travel. This baffling effect produce'd by the vane causes theconvexed surface to be air loaded while the bafile eliminates passage ofair along the concave or back side of the vane. Due to the `gradualdivergent curvature of the bafile vane, the air does not break away fromthe convex surface. However, the air Velocity diminishes progressivelyas the air travels towards the fan discharge. The reduction in airVelocity is due to the expanding area through which the air moves andthe diverging path the air is compelled to take due to the curvature ofthe vane.

The baifiing effect of the vanes causes the air to be interceded by theleading surfaces of the convex side of the vanes at a Velocity close tothat of the air leaving the impeller. This is accomplished with minimumlosses. The air is released by the vanes at the fan discharge withgreatly reduced Velocities. Thus, the initial kinetic energy of the airproduced by the action of the impeller is converted to a useful form ofpressure.

It was found Ithat the use of the concave side of the vane forconverting the kinetic energy of the air to pressure was not efiicient.The reason for this is because the air leaves the impeller withconsiderable rotative direction in the housing. Thus, if the vane wereso shaped as to load the concave side of the vane the successivebombardment of the air against the vane for the majority of its lengthwould tend to maintain the Velocity of the air rather than reduce theVelocity. This, of course, makes an effective air straightening vane butdoes not efficiently convert the kinetic energy of the air to pressure.The baffie vanes employed with this new fan purposely not only eliminatethe flow of air along the concave curvature but compel the air to clingand flow along the convex side of the vanes due to the bafling effectand the reasons stated above. This arrangement results in much higherconversion efficiencies. As the air moves along the conVeX vane 24 thereis a Velocity pressure at this early point which corresponds veryclosely with the Velocity pressure measured at the impeller; whereas,progressively along this vane, toward its outer end, there is a constantdrop in Velocity pressure.

The baflie vanes are so curved that their surface reaches or approachesan axial direction at the fan discharge. Since air tends to cling to asmooth and gradually curved surface, the air is drawn by the vane toalso discharge in a substantially aXial direction. Additional vanes ofthe air straightening variety may be added at the fan discharge ifdesired to give tiuer axial flow.

The positioning of the inner Corners of the leading edges of the vanesin close proximity to the rotative path o-f the impeller blades isimportant in order to form definite points of cutoff, but a slight spaceas shown should be allowed to avoid turbulence and noise that mightresult. I have found that where two or three vanes as shown areemployed, an efficient curvature of the vanes at their intersection withthe surface of fan housing 16 when projected by revolution to a plane,FIGURE 3, is substantially the involute of a circle whose radius isabout 21/2 times the extreme fan impeller diameter and where theordinate perpendicular to the base line runs parallel to the axis of theimpeller. The proper curvature of the vanes and the curvature of thecylindrical housing just beyond the point of cut oif of the vanes areimportant design features to successfully convert the kinetic energy ofthe air to static pressure. The curvature of the vanes regulates thespin Velocity of the air and the curvature of the cylindrical housingcontrols the passage of the air in a manner to cause the air to followthe dictates of the vanes.

Since the vanes curve gradually toward an axial direction, the airemerges from the discharge of the housing substantially in an axialdirection, the rotative spin imparted by the impeller beingsubstantially eliminated. It was found that the area between each vane24 and dotted line 34 (iFIG. 3) shown on the concave side of the vaneheld air in a static state. This is due to the direction of the spinVelocity of the air leaving the impeller which bypasses the concave sideof the vane due to the flatness of the vane along its leading surface.The back or concave side of the bafile vanes may be filled in or apartition may be added so as to isolate the area where air motion doesnot exist, if desired, without departing from the spirit of theinvention.

The preferred amount of turn or wrap of the vanes inside the |fanhousing may be expressed in degrees of the fan housing circumference.For instance, if the vanes make one complete turn inside the housing,the vanes would terminate 360 degrees from their point of origin. Itwill be obvious therefore, that the fan housing must have sutficientlength to provide the required degree of turn of the vanes as well asthe proper curvature of the vanes to effect the desired amount ofconversion of the total pressure produced by the impeller to staticpressure. I have found that vanes extending from 20 to circumferentialdegrees could be used depending on the number of vanes and the amount ofconversion desired.

A convenient method of obtaining the convolute shape of thevanes fromtheir point of origin to their termination aoeassa is to establish theangle formed by lines tangent to both the inner surface of the fanhousing and the points along the surface of the vanes where the vanesmeet the fan housing with a plane orthogonal to the impeller axis, asshown schematically in FIG. 14.

I have found that a tangent line, as described above, to the point oforigin of the vanes may form an angle with the plane varying between to30 degrees. The angle between the limits of 5 to 30 degrees beingselected depending on the number of vanes and the amount of pressureConversion desired. Where three vanes are employed it has been foundthat a generally suitable angle for a tan-gent line at the point oforigin of the vanes is about 20 degrees.

The curvature of the vanes 24, FIG. 14, may also be determinedmathematically by obtaining the values of (X) and (Y) for various angles0 or the angles formed by the sweep of the radius arm (E) as follows:

Where K=1.5 to 5 D=Extreme irnpeller diameter WKDH S 180 For large fanswith wheel diameters exceeding 24 inchcs, six or more vanes may be usedto reduce the length of the fan housing. In the case where six vanes areused the vanes may extend about 60 circumferential degrees, or as littleas 20 circumferential degrees depending on the number of vanes.

Impellers with blades curved as shown in FIGURES 4, 5, 6, 7, 8 and 9were found to perform satisfactorily in my new fan. The impellers shownin FIGS. 4, 5, 6, and 7 are all backward curved types, while FIGS. 8 and9 show forward curved blading. The impeller shown in FIG. 5 requires ahigher rotative speed than radial blade impeller of FIG. 1 to producethe same quantity of air and pressure, while impellers shown in FIGS. 8and 9, have lower rotative speeds. The impeller shown in FIG. 5 hasnon-overloa'ding power characteristics which is advantageous where suchfeatures are desired. Slight modifications of the curvature of the vanes24 is desirable for efiicient operation when using impellers ofdifferent blading such as backward or forward curved. The reason forthis is because each type of blading directs the air leaving theimpeller at a slightly different angle in relation to the vanes and thehousing.

In FIG. 10 the impeller shaft 36 is shown driven th-rough a pulley 38thereon, and a V-belt 40, the shaft being mounted in bearings 42.

In this figure the thimble 14 of FIG. 1 is replaced with a long,receding, conical shaped air dilfuser 44. The three vanes 24 extend fromthe housing 16 to the cone as shown in FIGURE 11.

This diffuser cone permits the air to leave the fan discharge atslightly lower velocities without losses due to turbulence and,consequently, a greater amount of conversion of the kinetic energy ofthe air to static pressure.

In FIGURE 12 the impeller is shown mounted directly on the shaft of amotor 46. The discharge thimble 48 is shown slightly tapered which hasbeen found tends to reduce noise, even where a narrow thimble isemployed. In the case where the diameter of the motor housing isapproximately equal to the diameter of the thimble, the motor casing canserve to do the work of the thimble.

It also has been found that the performance of my new fan can be variedwithin limits, by varying the degree of curvature of the vanes. Forinstance, by reducing angle "A" (FIG. 3) formed between a tangent line Bto a point along the curvature of projection of the vane with therotative parts of the blades, the pressure developed by the fan tends toincrease while the volume decreases. If such angle A is increased, thepressure developed by the fan tends to decrease while the volume tendsto increase.

With my improved fan, the vanes or baffles 24 complete to a desireddegree the conversion of kinetic energy to static pressure, at a pointclose to the discharge of the cylindrical casing, at which point themaximum pressure is obtained. This point of maximum pressure is remotelypositioned from the leading edges of the vanes or points of cutof.Therefore, the amount of leakage back through the wheel is greatlyreduced and is substantially negligible.

By increasing the number of vanes 24 from two to four `and consequentincrease in the number of points of cutoif, the pressure and volume tendto increase, which is a decided advantage. Apart from the increasedpressure produced by the addition of one or more vanes, the amount ofwheel exposure may be substantially reduced or entirely eliminated. Thisreduces the loss due to wheel exposure at the discharge which occurswith centrifugal fans in a spiral housing, the latter havingconsiderable exposure of the wheel when viewed from the discharge of thehousing.

Since the area of the point of air discharge from the impeller issubstantially 'the same as the area between the thimble and the housing,there is no lateral expansion as in the case of centrifugal fans withspiral housings, and thus distribution losses are negligible. Thisrepresents an appreciable increase in efficiency.

My improved fan occupies much less space than the present centrifugalfan. It may be mounted in any desired direction of flow and as part of astraight line flow from inlet duet to discharge duct. The fan can beinstalled in out of way places, and saves floor space which today is atsuch a high premium. Manufacturing costs as well as installation costsare lower than with the present day blowers.

The fan does not occupy any greater space than vane axial fans incommercial use at the present time. However, it out-performs the vaneaxial fan. Also, my fan operates at much lower speeds than the vaneaxial fan for the same working conditions, which is one of the reasonsit is much quieter. The vane axial fan when employed for use whereconsiderable resistance is encountered, has been found to be very noisy.Consequently its use is being restricted chiefiy to industrial purposes.On the other hand my new fan can be used for air-conditioning andgeneral ventilating purposes where quietness is essential regardless ofthe resistance encountered with such systems.

The scope of use of my fan is wide and varied, can be used in any fanapplication where centrifugal blowers or vane axial fans are employedtoday with important advantages over both, but without the disadvantagesabove pointed out.

What I claim is:

1. In a fan of the class described, a housing having a cylindrical innerbore surface., a rotary impeller positioned concentrically within thehousing bore surface and comprising a hub, a backplate carried by thehub, and a plurality of blades on the front side of the backplate, saidblades having end extensions projecting beyond the periphery of thebackplate, an inlet cone in front of said impeller, a substantiallycylindrical discharge thimble having its front edge arranged closelyadjacent the rear edge of said backplate, and a plurality of vanes ofconvolute form projecting inwardly from the inner bore surface of saidhousing and substantially orthogonal thereto and extending generallylongitudinally thereof with their forward ends extending over thecylindrical surface of the thimble to points in proximity to the frontend edge of said thimble, said vanes being sufficiently spaced apart sothat the air flow is not confined between two adjacent vanes and beinggradually curved in the general direction of rotation of said impeller,each of said vanes presenting a convex surface to the air delivered bysaid impeller and defining with the rotative path of the outer edges ofthe impeller blades a constantly increasing space, substantially all ofthe air from said impeller being delivered to said convex surfaces ofthe vanes and directed and guided therealong through said constantlyincreasing spaces, whereby the kinetic energy of the air is converted tostatic pressure as the air travels to the dscharge end of said housing.

2. In a fan of the class described, a housing having a cylindrical innerbore surface, a rotary impeller positioned concentrically within thehousing bore surface and comprising a hub, a backplate carried by thehub, and a plurality of blades on the front side of the backplate, Saidblades having end extensions projecting beyond the periphery of thebackplate, an inlet cone in front of said impeller, a shroud for theblades having a leading edge substantially contiguous with the trailingedge of said inlet cone, a substantially cylindrical discharge thimblehaving its front edge arranged closely adjacent the rear edge of saidbackplate, and a plurality of vanes of convolute form projectinginwardly from the inner bore surface of said housing and substantiallyorthogonal thereto and extending generally longitudinally thereof withtheir forward ends extending over the cylindrical surface of the thimbleto points in proximity to the front end edge of said thimble,' saidvanes being sufficiently spaced apart so that the air flow is notconfined between two adjacent vanes and being gradually curved in thegeneral direction of rotation of said impeller, each of said vanespresenting a conveX surface to the air delivered by said impeller anddefining with the rotative path of the outer edges of the impellerblades a constantly increasing space, substantially all of the air fromsaid impeller being delivered to said convex surfaces of the vanes anddirected and guided therealong through 'said constantly increasingspaces, whereby the kinetic energy of the air is converted to staticpressure as the air travels t'o the discharge end of said housing.

3. In a fan of the class described, a housing having a cylindrical innerbore surface, a centrifugal rotary impeller positioned concentricallywithin the housing bore surface and comprising a hub, a substantiallyfiat backplate having va rounded peripheral edge carried by the hub, anda plurality of blades on the front side of the backplate, said bladeshaving end extensions projecting beyond the periphery of the backplate,an inlet cone in front of said impeller, an angular shroud for theblades having a leading edge -substantially continguous with thetrailing edge of said inlet cone, a substantially cylindrical dischargethimble having its front edge arranged closely adjacent the rear edge ofsaid backplate, and a plurality of vanes of convolute form projectinginwardly from the innner bore surface of said housing and substantiallyorthogonal thereto and eXtending generally longitudinally thereof withtheir 'forward ends exitending over the cylindrical surface of thethimble lto points in proximity to the front end edge of said thimble,said vanes being sufiiciently spaced apart so that the air flow is notconfined between two adjacent vanes and being gradually curved in thegeneral direction of rotation of said impeller, each of said vanespresenting a convex surface to the air delivered by said impeller anddefining with the rotative path of the outer edges of the impellerblades a constantly increasing space, substantially all of the air fromsaid impeller being delivered to said convex surfaces of the vanes anddirected and guided therealong through said constantly increasingspaces, whereby the kinetic energy of the air is converted to staticpressure as the air travels to the discharge end of said housing.

4. Apparatus as defined in claim 3, wherein the trailing edges of saidblades are inclined inwardly and rearwardly in relationship to theleading edges of said vanes and wherein said leading edges are inclinedoutwardly and rearwardly.

5. Apparatus as defined in claim 3, wherein the curvature of each vaneis such that a tangent line common to both the surface of the vane andthe surface of the housing bore at t.e leading edge of the vane forms anangle with a plane orthogonal with said longitudinal aXis of between to30, and each subsequent tangent line advancing unit degreeseircumferentially along said housing bore surface from the leading edgethereof and common to the aforesaid vane and bore -surfaces formsprogressively increasing angles with said plane and wherein said vanesextending circumferentially from their respective leading edges to theirtrailing ends thereof through an are at least 10 and no greater than 160of said housing surface.

6. In a fan of the class described, a housing having a cylindrical innerbore surface, a rotary centrifugal impeller positioned concentricallywithin the housing bore surface and comprising a hub, a backplatecarried by the hub, and a plurality of blades on the front side of thebackplate, said blades having end extensions projecting beyond theperiphery of the backplate, an inlet cone in front of said impeller, asubstantially cylindrical discharge thiinble having its front edgearranged closely 'adjacent the rear edge of said backplate, and aplurality of vanes of convolute form projecting inwardly from the innerbore surface of said housing and substantially orthogonal thereto andextending generally longitudinally thereof with their forward endsextending over the cylindrical surface of the thiinble to points inproXimity to the front end edge of said thimble, said vanes beingsufliciently spaced apart so that the air flow is not confined betweentwo adjacent vanes and being gradually curved in the general directionof rotation of said impeller, each of said vanes adjacent said thirnblepresenting a substantially fiat surface portion to intercept the airfrom said centrifugal impeller and a progressively conveX surfacetherealong and defining with the rotative path of the outer edges of theimpeller blades a constantly increasing space, substantially all of theair from said impeller being delivered to 'said convex surfaces of thevanes and directed and guided therealong through said constantlyincreasing spaces, whereby the kinetic energy of the air is converted tostatic pressure as the air travels to the discharge end of said housing.

References Cited in the file of this patent UNITED STATES PATENTS 7,883Bennet Jan. 7, 1851 86,264 White et al. Jan. 26, 1869 100,838 AndrewsMar. 15, 1870 1,135,296 Krogh Apr. 13, 1915 1,261,457 Stott Apr. 2, 19181,928,839 Marsden Oct. 3, 1933 2,029,813 De May Feb. 4, 1936 2,273,4-20Schot't Feb. 17, 1942 2,398,523 DeIFlorl Apr. 16, 1946 2,427,032 Frolleret al. Sept. 9, 1947 2,483,335 Davis Sept. 27, 1949 2,555,576 CriquiJune 5, 1951 2,609,141 Aue Sept. 2, 1952 2,620,624 Wislicenus Dee. 9,1952 2,7l3,967 Schneider et al. July 26, 1955 2,859,910 Stalker Nov. 11,1958 FOREIGN PATENTS 1,379 Great Britain of 1853 1,446 Great Britain of1888 257,111 Great Britain Aug. 26, 1926 282,797 Great Britain Oct. 11,1928 381,431 Great Britain Oct. 6, 1932 505,078 Great Britain May 2,1939 583,664 Great Britain Dec. 24, 1946 604,121 Great Britain June 29,1948 636,290 Great Britain Apr. 26, 1950 713,617 Germany Nov. 11, 1941913,354 France May 27, 1946

